Re: [PATCH 0/2] Re: Excess dmesg output from ACPIPHP on boot

From: Rafael J. Wysocki
Date: Fri Sep 06 2013 - 19:35:44 EST

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On Friday, September 06, 2013 09:36:08 AM Alex Williamson wrote:
> On Fri, 2013-09-06 at 15:42 +0200, Rafael J. Wysocki wrote:
> > On Friday, September 06, 2013 01:36:28 AM Rafael J. Wysocki wrote:
> > > On Thursday, September 05, 2013 05:08:03 PM Alex Williamson wrote:
> > > > On Fri, 2013-09-06 at 00:40 +0200, Rafael J. Wysocki wrote:
> > > > > On Thursday, September 05, 2013 04:17:25 PM Alex Williamson wrote:
> > > > > > On Thu, 2013-09-05 at 23:39 +0200, Rafael J. Wysocki wrote:
> > > > > > > On Thursday, September 05, 2013 09:44:26 PM Rafael J. Wysocki wrote:
> > > > > > > > On Thursday, September 05, 2013 08:21:41 AM Alex Williamson wrote:
> > > > > > >
> > > > > > > [...]
> > > > > > >
> > > > > > > > > >
> > > > > > > > > > [ 18.288122] pci 0000:00:00.0: no hotplug settings from platform
> > > > > > > > > > [ 18.288127] pcieport 0000:00:01.0: no hotplug settings from platform
> > > > > > > > > > [ 18.288142] pci 0000:01:00.0: no hotplug settings from platform
> > > > > > > > > > [ 18.288157] pci 0000:01:00.1: no hotplug settings from platform
> > > > > > > > > > [ 18.288162] pcieport 0000:00:03.0: no hotplug settings from platform
> > > > > > > > > > [ 18.288176] pci 0000:02:00.0: no hotplug settings from platform
> > > > > > > > > > [ 18.288190] pci 0000:02:00.1: no hotplug settings from platform
> > > > > > > > > > [ 18.288195] pcieport 0000:00:07.0: no hotplug settings from platform
> > > > > > > > > > [ 18.288209] pci 0000:03:00.0: no hotplug settings from platform
> > > > > > > > > > [ 18.288224] pci 0000:03:00.1: no hotplug settings from platform
> > > > > > > > > > [ 18.288228] pci 0000:00:14.0: no hotplug settings from platform
> > > > > > > > > > [ 18.288233] pci 0000:00:14.1: no hotplug settings from platform
> > > > > > > > > > [ 18.288237] pci 0000:00:14.2: no hotplug settings from platform
> > > > > > > > > > [ 18.288242] pci 0000:00:16.0: no hotplug settings from platform
> > > > > > > > > > [ 18.288247] pci 0000:00:16.1: no hotplug settings from platform
> > > > > > > > > > [ 18.288251] pci 0000:00:16.2: no hotplug settings from platform
> > > > > > > > > > [ 18.288256] pci 0000:00:16.3: no hotplug settings from platform
> > > > > > > > > > [ 18.288260] pci 0000:00:16.4: no hotplug settings from platform
> > > > > > > > > > [ 18.288265] pci 0000:00:16.5: no hotplug settings from platform
> > > > > > > > > > [ 18.288269] pci 0000:00:16.6: no hotplug settings from platform
> > > > > > > > > > [ 18.288274] pci 0000:00:16.7: no hotplug settings from platform
> > > > > > > > > > [ 18.288278] pci 0000:00:1a.0: no hotplug settings from platform
> > > > > > > > > > [ 18.288279] pci 0000:00:1a.0: using default PCI settings
> > > > > > > > > > [ 18.288292] pci 0000:00:1a.1: no hotplug settings from platform
> > > > > > > > > > [ 18.288293] pci 0000:00:1a.1: using default PCI settings
> > > > > > > > > > [ 18.288307] ehci-pci 0000:00:1a.7: no hotplug settings from platform
> > > > > > > > > > [ 18.288308] ehci-pci 0000:00:1a.7: using default PCI settings
> > > > > > > > > > [ 18.288322] pci 0000:00:1b.0: no hotplug settings from platform
> > > > > > > > > > [ 18.288327] pcieport 0000:00:1c.0: no hotplug settings from platform
> > > > > > > > > > [ 18.288332] pcieport 0000:00:1c.4: no hotplug settings from platform
> > > > > > > > > > [ 18.288344] pci 0000:05:00.0: no hotplug settings from platform
> > > > > > > > > > [ 18.288349] pci 0000:00:1d.0: no hotplug settings from platform
> > > > > > > > > > [ 18.288350] pci 0000:00:1d.0: using default PCI settings
> > > > > > > > > > [ 18.288360] pci 0000:00:1d.1: no hotplug settings from platform
> > > > > > > > > > [ 18.288361] pci 0000:00:1d.1: using default PCI settings
> > > > > > > > > > [ 18.288374] pci 0000:00:1d.2: no hotplug settings from platform
> > > > > > > > > > [ 18.288374] pci 0000:00:1d.2: using default PCI settings
> > > > > > > > > > [ 18.288387] pci 0000:00:1d.3: no hotplug settings from platform
> > > > > > > > > > [ 18.288387] pci 0000:00:1d.3: using default PCI settings
> > > > > > > > > >
> > > > > > > > > > The boot is noticeably slower. What's going to happen on systems that
> > > > > > > > > > actually have a significant I/O topology vs my little workstation?
> > > > > > > >
> > > > > > > > That depends on how many bus check/device check events they generate on boot.
> > > > > > > >
> > > > > > > > My test machines don't generate them during boot at all (even the one with
> > > > > > > > a Thunderbolt connector), so I don't see the messages in question during boot
> > > > > > > > on any of them. Mika doesn't see them either I suppose, or he would have told
> > > > > > > > me about that before.
> > > > > > > >
> > > > > > > > And let's just make it clear that it is not usual or even OK to generate bus
> > > > > > > > checks or device checks during boot like this. And since the changes in
> > > > > > > > question have been in linux-next since right after the 3.11 merge window, I
> > > > > > > > think that someone would have complained already had that been a common issue.
> > > > > > > >
> > > > > > > > Of course, we need to deal with that somehow nevertheless. :-)
> > > > > > > >
> > > > > > > > > Just to give you an idea:
> > > > > > > > >
> > > > > > > > > CONFIG_HOTPLUG_PCI_ACPI=y
> > > > > > > > >
> > > > > > > > > $ dmesg | wc
> > > > > > > > > 5697 49935 384368
> > > > > > > > >
> > > > > > > > > $ dmesg | tail --lines=1
> > > > > > > > > [ 53.137123] Ebtables v2.0 registered
> > > > > > > > >
> > > > > > > > > -- vs --
> > > > > > > > >
> > > > > > > > > # CONFIG_HOTPLUG_PCI_ACPI is not set
> > > > > > > > >
> > > > > > > > > $ dmesg | wc
> > > > > > > > > 1053 9176 71652
> > > > > > > > >
> > > > > > > > > $dmesg | tail --lines=1
> > > > > > > > > [ 28.917220] Ebtables v2.0 registered
> > > > > > > > >
> > > > > > > > > So it spews out 5x more output with acpiphp enabled and takes and extra
> > > > > > > > > 24s to boot (nearly 2x). Not good.
> > > > > > > >
> > > > > > > > The "no hotplug settings from platform" message is from pci_configure_slot().
> > > > > > > > I think the messages you're seeing are from the call to it in
> > > > > > > > acpiphp_set_hpp_values() which is called by enable_slot().
> > > > > > > >
> > > > > > > > There, I think, we can simply check the return value of pci_scan_slot() and
> > > > > > > > if that is 0 (no new devices), we can just skip everything under the call to
> > > > > > > > __pci_bus_assign_resources().
> > > > > > > >
> > > > > > > > However, we can't skip the scanning of bridges, if any, because there may be
> > > > > > > > new devices below them and I guess that's what takes so much time on your
> > > > > > > > machine.
> > > > > > >
> > > > > > > OK, one piece is missing. We may need to evaluate _OSC after handling each
> > > > > > > event to let the platform know the status.
> > > > > > >
> > > > > > > Can you please check if the appended patch makes any difference (with the
> > > > > > > previous fix applied, of course)?
> > > > > > >
> > > > > > > If fact, it is two patches combined. One of them optimizes enable_slot()
> > > > > > > slightly and the other adds the missing _OSC evaluation.
> > > > > >
> > > > > > Better, still double the output:
> > > > > >
> > > > > > $ dmesg | wc
> > > > > > 2169 19047 152710
> > > > >
> > > > > I see.
> > > > >
> > > > > What about the timing?
> > > >
> > > > ~40s below vs ~29s for acpiphp config'd out above.
> > >
> > > Well, that's better than before.
> > >
> > > I'll prepare "official" patches with the last changes then too.
> >
> > The patches follow as [1/2] and [2/2]. The change in enable_slot() is
> > literally the same, but the _OST patch is somewhat different, although the
> > changes mostly affect the eject code path and the notifies that we don't
> > actually handle, so they should not matter on your machine.
>
> Tested-by: Alex Williamson <alex.williamson@xxxxxxxxxx>

Thanks!

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Next message: Linus Torvalds: "Re: [GIT] HID for 3.12 merge window"
Previous message: Rafael J. Wysocki: "Re: [PATCH 1/2] ACPI / hotplug / PCI: Avoid doing too much for spurious notifies"
In reply to: Alex Williamson: "Re: [PATCH 0/2] Re: Excess dmesg output from ACPIPHP on boot"
Next in thread: Lan Tianyu: "Re: [PATCH 25/30] ACPI / hotplug / PCI: Check for new devices onenabled slots"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]